About This Gigapan

Higher-resolution (but poorly stitched) version of this Gigapan: gigapan.com/gigapans/148648From atop Mary's Peak, you can see all the way from the Pacific Ocean across the Coast Range (which Mary's Peak is part of) and the Willamette Valley to the Cascades. This panorama encompasses over 180 degrees of that view- westward on the left, eastward on the right.
This is a subduction zone, where the oceanic plate is sinking beneath the continental plate. The Coast Range was driven up by the compression between these colliding plates. Water released from the subducting oceanic plate causes hot rock beneath the continent to melt, bubbling up and erupting to form volcanoes that make the Cascades.
From this vantage point, you can see the whole shebang.
Visibility was excellent on this day due to a temperature inversion-- you can see that the Wilammette Valley is filled with low-level clouds. That is indeed Washington's Mt. Rainier off in the distance-- it's about 185 miles away.